P0440 on Chevrolet: How to Diagnose & Fix
Evaporative Emission Control System Malfunction
1 Chevrolet model · 1 documented issue · $120-$450 repair
P0440 on Chevrolet by model: symptoms, diagnosis and fix
A very common GMT800 Silverado problem is contamination of the EVAP canister vent valve/solenoid by dust, road debris, or water intrusion. When the vent cannot flow properly, the truck sets EVAP leak or vent performance codes and may repeatedly shut off the gas pump during refueling. GM issued service bulletins and updated vent relocation kits for trucks used in dusty environments.
Common Symptoms
- check engine light
- fuel nozzle clicks off repeatedly while filling
- EVAP small or large leak codes
- failed emissions inspection
- intermittent fuel smell near rear of truck
How to Fix
Diagnosis includes smoke testing the EVAP system, commanding the vent valve with a scan tool, and inspecting the vent hose/filter for blockage. Repair usually involves replacing the vent solenoid and installing the updated relocated vent hose/filter kit to move the inlet away from road splash and dust. Clearing codes without updating the vent routing often leads to repeat failures.
Sources for this issue (1)
P0440 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0440 mean on a Chevrolet?
P0440 stands for "Evaporative Emission Control System Malfunction." This code indicates a general malfunction in the Evaporative Emission Control (EVAP) system, which captures fuel vapors from the gas tank and routes them to be burned by the engine instead of escaping into the air. The computer ran a self-test and detected the sealed vapor system isn't holding pressure or vacuum correctly, often signaling a leak somewhere in the system. The most frequent and easiest cause is a loose or faulty gas cap. The car will run normally, but it will fail an emissions test and may smell faintly of fuel. On Chevrolet it is documented across 1 model: Silverado 1500.
What are the most common causes of P0440?
The most common causes of P0440 are: Loose, damaged, or missing gas cap, Cracked or disconnected EVAP hose, Faulty purge valve/solenoid, Faulty vent valve/solenoid, Leaking charcoal canister, Damaged fuel tank filler neck or seal, Faulty leak detection pump or pressure sensor. The specific cause varies by vehicle.
How much does it cost to fix P0440 on a Chevrolet?
Published repair estimates on Chevrolet range from $120 to $450 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0440 on a different make?
View P0440 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.